remove duplicate role grid from RCTViewManager (facebook#35932)

Summary:
Fix warning: duplicate key in dictionary literal. Different PRs tried to fix this issue at the same time and introduced a duplicate. Related fabOnReact@55c0df4 fabOnReact@f3d9f2e

## Changelog

[IOS] [FIXED] - remove duplicate role grid from RCTViewManager

Pull Request resolved: facebook#35932

Test Plan: <img width="1920" alt="duplicated grid role on iOS" src="https://user-images.githubusercontent.com/24992535/214054716-d79dec11-2b5c-4780-a4af-08d50be4a1a2.png">

Reviewed By: sammy-SC

Differential Revision: D42677641

Pulled By: jacdebug

fbshipit-source-id: f3eaa99ce89d7f9602843fde0dc0f371300e7052

React/Views/RCTViewManager.m

@@ -64,7 +64,6 @@ @implementation RCTConvert (UIAccessibilityTraits)
       @"tablist" : @(UIAccessibilityTraitNone),
       @"timer" : @(UIAccessibilityTraitNone),
       @"toolbar" : @(UIAccessibilityTraitNone),
-      @"grid" : @(UIAccessibilityTraitNone),
       @"pager" : @(UIAccessibilityTraitNone),
       @"scrollview" : @(UIAccessibilityTraitNone),
       @"horizontalscrollview" : @(UIAccessibilityTraitNone),